Dynamis Divergence came out in 2016. It's 8-9 years old at this point. Also, SE has already lessened the difficulty in Dyna-D by making AF unlocks available by killing 100 mobs, vs the wave 1 mid-boss. So, I don't think lowering it would be a good idea without something to replace it's perceived difficulty.

However, I think you're requesting content that sounds more like Omen, which is more or less any "any jobs can participate" and is more or less, a free-for-all. (Yes, there are objectives, but the objectives don't give partial credit. You just do all the objectives, to 100% completion, or you don't get a basic amount of Omens to contribute to your evaluation or "a spectral light").

I think it's much more likely SE makes Dynamis Divergence harder or configurable, similar to the progression that is available in Incursion (i.e. you can choose the level between 123-143, I think). So, I personally would like to see Dynamis-Divergence have a choice between 140-160 Item Level, given it's age.